Bus networks are used in a variety of fields and applications to interconnect devices and allow communication, power transmission, and other functionality. One such bus network is known as a Digital Addressable Lighting Interface (DALI), which is a bus architecture standard used in controlling devices in a building (such as sensors, lighting devices, and shades). DALI provides a two-wire bus that allows power to be supplied to, and communication between, devices on the bus. In the DALI architecture, the presence of voltage indicates a first state (i.e., a logical “1”), while the shorting of the two wires by any device on the bus indicates a second state (i.e., a logical “0”). In this manner, devices can use the two-wire DALI bus to communicate with each other.
In some bus network architectures, including DALI, the amount of power that can be supplied to devices on the bus may be limited by the architecture specification, which may in turn limit the number of devices that can be connected to the bus. In the DALI architecture, for example, power is typically supplied at 16.5V (22.5V maximum) with a current limit of 250 mA. According to the DALI specification, up to sixty-four devices can theoretically be coupled to a DALI bus, but many DALI-compatible devices can draw, for example, up to 40 mA each, effectively limiting the number of such devices that can actually be connected to the bus.
Similarly, the impedance of the bus wiring can limit the number of devices that can be connected to a bus. For example, DALI bus networks are often deployed in large buildings, requiring long lengths of wiring to be run to the devices in the building. Conventional DALI networks use lower gauge (i.e., thicker) wires as the bus gets longer, which is not only more expensive than higher gauge wire, but also increases the overall complexity of installation. Installers of such buses may have to work with multiple spools of wire, which can increase the time and cost to install a bus network.
Embodiments in this disclosure address these and other issues.